(PI,PI, N) REACTIONS ON MG-25 AND AU-197

Activation cross sections have been measured for the reactions Mg25(π±,π±N)Na24 and Au197(π±,π±N)Au196 between 100 and 300 MeV. The cross section ratios Rp=σ(π+)σ(π- ) and Rp=σ(π-)σ(π+) are smaller than the corresponding free-particle ratios in all cases. Comparisons with the predictions of intranuclear cascade calculations and the nucleon charge-exchange model indicate that the former gives good agreement for a heavy nucleus but not for light nuclei, while the inverse is true for the latter model. NUCLEAR REACTIONS Mg25(π±, π±N) Na24, Au197(π±, π±N) Au196, E=100-300 MeV; measured σ (activation). Compared with intranuclear cascade calculation, nucleon charge-exchange model. © 1979 The American Physical Society.